target/arm: Separate cpu types max-v8 and max-v9

Do not include v9-only features in "max-v8".
Do not include the prohibited v8 features in "max-v9".
In aarch64 tcg mode, define "max" as "max-v9".

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20260827041557.775080-7-richard.henderson@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>